STUDIES ON THE STRIPED BASS OF THE ATLANTIC COAST 



27 



1937 exhibited approximately the same amount of growth (8-9 cm.) from June through 

 October as fish of the same age in 1936, but it wUl be noticed that they consistently 

 averaged at least 2 cm. larger over this entire period. Thus the modes of the length- 

 frequency curves of the 2-year-olds of 1937 moved from 31 cm. in June to 39 cm. in 

 October. However, the 3-year-olds of 1937, although growing the same amount as 

 fish of the same age in 1936 over an equivalent period of time, averaged 2 cm. smaller 

 throughout, the modes moving from approximately 38 cm. in June to 46 cm. in Octo- 

 ber. The comparison of any of the monthly length-frequency curves in 1936 with its 

 counterpart in 1937 clearly shows that the 2-year-olds in 1937 were distinctly larger 

 than those of 1936, while the 3-year-olds of 1937 were definitely smaller than fish of the 

 same age in 1936. The members of the dominant year-class of 1934 (2 years old in 

 1936 and 3 years old in 1937) therefore appear to have been below average size. 



GROWTH OF 2- AND 3-YEAR-OLD STRIPED BASS SEINED IN 

 CONNECTICUT WATERS DURING 1936 AND 1937 



CMS "j 



1CMFS It 



Fiourk 18.— The growth of the 2- and 3-year-old striped bass seined in Connecticut waters during 1936 aDd 1937. The curves are 

 smoothed in every case by a moving average of threes. The numbers of fish making up each curve have not been equalized 

 except in that for September 1936, where the total number of fish was divided by three. The dotted line in the June 1937, 

 length-frequency curves is a repetition of curve for the 2-year-olds in October 1936, and is included for the purpose of comparing 

 the 2-year-olds of October 1936, with the 3-year-olds of June 1937 (members of the same year -class) (see Table 12 for original 

 measurements). 



They were consistently smaller than the fish which were born in 1933 or 1935 were 

 at equivalent ages; both the 1933 and 1935 year-classes were few in numbers by com- 



fmrison to the dominant 1934 year-class. It is quite clear that this lesser average 

 ength of the members of the dominant 1934 year-class developed before the individuals 

 became 2 years old. The smaller sizes of the individuals making up this dominant 

 age-group agree well with Jensen's (1932) studies on plaice (Pleuronectes platessa) in 

 the North Sea, where it was shown that a strong year-class checks the growth of the 

 fish in this age-group. Jensen (loc. cit.) also points out that the principle of the 

 smaller-than-average size of the individuals making up a dominant year-class, at least 

 in plaice, also appears true from Thursby-Pelham's work, where it is shown that the 

 rich year-class of 1922 was distinguished by a small average length. This is explained 

 by Jensen on the basis of increased competition for food among the members of the 



